<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt"><div>I think but using a <span style="font-size: 12pt;">quadtree approach there is a problem, and it is none other than the construction of the quadtree itself for so big data.</span></div><div style="color: rgb(0, 0, 0); font-size: 12pt; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span style="font-size: 12pt;"><br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">IMHO I would use a specific provider (with a specific featureiterator) reading sequentially the LAS file and discarding points before fetch it to renderer using the
RectangleFilter of current FeatureRequest. It avoid create many-many QgsFeature's that after are discarded in renderer side.</div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">I use this technique in a personal viewer, and after first read of file (the file is cached in SO), the following drawings are quite fast.</div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica
Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;">Alvaro</div><div><br></div><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; margin-top: 5px; padding-left: 5px;"> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 12pt;"> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1"> <font size="2" face="Arial"> <b><span style="font-weight:bold;">De:</span></b> Jean-Roc Morreale <jr.morreale@enoreth.net><br> <b><span style="font-weight: bold;">Para:</span></b> qgis-developer@lists.osgeo.org <br> <b><span style="font-weight: bold;">Enviado:</span></b> Miércoles 29 de enero de 2014 13:32<br> <b><span style="font-weight: bold;">Asunto:</span></b> Re: [Qgis-developer] Lidar data into QGIS<br> </font> </div>
<div class="y_msg_container"><br>Can it performs fast enough to display hundred millions points or <br clear="none">billions at once ? Does it leverage a quadtree approach ?<br clear="none"><div class="yqt3999780934" id="yqtfd78773"><br clear="none">Le 2014-01-29 12:55, A Huarte a écrit :<br clear="none">> yes, it can be implemented on renderer level (Martin Dobias propose<br clear="none">> it) or on featureiterator level similar to current simplification<br clear="none">> classes for line and polygons<br clear="none">> <br clear="none">> I think it is pending for a test of performance<br clear="none">> Best Regards<br clear="none">> Alvaro<br clear="none"><br clear="none"><br clear="none">_______________________________________________<br clear="none">Qgis-developer mailing list<br clear="none"><a shape="rect" ymailto="mailto:Qgis-developer@lists.osgeo.org"
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